Re: [PATCH 2/2] sched/fair: Scale wakeup granularity relative to nr_running

[Vincent Guittot]

On Thu, 23 Sept 2021 at 11:22, Mike Galbraith <efault@xxxxxx> wrote:
>
> On Thu, 2021-09-23 at 10:40 +0200, Vincent Guittot wrote:
> >
> > a 100us value should even be enough to fix Mel's problem without
> > impacting common wakeup preemption cases.
>
> It'd be nice if it turn out to be something that simple, but color me
> skeptical.  I've tried various preemption throttling schemes, and while

Let's see what the results will show. I tend to agree that this will
not be enough to cover all use cases and I don't see any other way to
cover all cases than getting some inputs from the threads about their
latency fairness which bring us back to some kind of latency niceness
value

> it was trivial to get promising results, my scheme always managed to
> harm something.  Everything I ever tried, I ended up tossing.
>
>         -Mike